Tensioning instrument

ABSTRACT

A bone plate system for securing a plurality of bones is provided including a plate member, a locking device of the bone plate, and a surgical cable having a trailing end for being connected to the bone plate and a leading end for being advanced around the bones and into the locking device. The surgical cable may be tensioned to approximate the bones, urge the bones together, and seat the bone plate against the bones. The locking device may be reconfigured to a locked configuration to fix the bone plate to the surgical cable. The bone plate further includes a plurality of throughbores for receiving bone anchors that rigidly fix the bone plate to the bones. The bone plate system utilizes the tensile strength of the surgical cable and the rigid fixation between the bone anchors and the bone plate to resist relative movement of the bones.

CROSS REFERENCE TO RELATED APPLICATIONS

The application is a divisional of U.S. patent application Ser. No.13/837,615, filed Mar. 15, 2013, which claims the benefit of U.S. PatentApplication No. 61/728,930 filed Nov. 21, 2012, which are both herebyincorporated by reference in their entireties.

FIELD OF THE INVENTION

The invention relates to a bone plate system and, more particularly, toa bone plate system for securing and stabilizing a plurality of bones.

BACKGROUND OF THE INVENTION

There are presently many different types of plate and fixture systemsfor securing bones so that the secured bones may fuse or heal. As usedherein, the term bone may refer to a bone or a portion of a bone. Oneapplication for plate and fixture systems is in the field ofcardiovascular surgery, where access to a patient's heart may beobtained by cutting the sternum of the patient longitudinally from themanubrium through the xiphoid process. Cutting the sternumlongitudinally creates halves of the sternum that may be separated toprovide access to the chest cavity. After the patient's heart isoperated upon, the sternal halves are brought back together and securedto one another. One approach for securing the sternal halves involveslooping a metal wire around the sternal halves and twisting ends of thewire to secure the wire in tight engagement extending about the cutsternum bone halves. This process is repeated at several longitudinallyspaced positions along the cut sternum in order to restrict separationand shifting of the sternal halves post-surgery. However, the twistedwires may loosen over time and permit relative movement of the sternalhalves which adversely affects post-operative fusion of the sternalhalves.

SUMMARY OF THE INVENTION

In accordance with one aspect, a bone plate system is provided forsecuring and stabilizing portions of one or more bones, such as halvesof a sternum after the sternum has been cut longitudinally to provideaccess to an underlying chest cavity. The bone plate system includes abone plate, a cable configured to be looped around the portions of theone or more bones and connected to the bone plate, and opposite halvesof the bone plate that are laterally spaced apart from each other andwhich are configured for engaging a bone portion on either side of anincision that separates the bone portions. The bone plate has a lockingdevice that interconnects and extends laterally between the spaced boneplate halves and resists relative movement therebetween. The lockingdevice has an unlocked configuration that allows the cable to be shiftedrelative to the bone plate as tension is applied to the cable.Tensioning the cable tightly wraps the cable about the bone portions,approximates the bone portions together, and draws the bone platetightly against the approximated bone portions to rapidly andefficiently produce a construct of the bone plate, cable, andapproximated bone portions.

Once the cable has been tightened to a desired tension, the lockingdevice of the bone plate may be reconfigured to a locked configurationwhich rigidly fixes the cable to the bone plate and secures the boneplate and cable about the bones. The bone plate halves include aplurality of throughbores for receiving bone anchors for anchoring thebone plate halves in engagement with the bone portions. In this manner,the bone plate system utilizes both the high tensile strength of thecable and the rigid fixation of the bone anchors to the bone plate toprovide two load bearing mechanisms which resist separation and movementof the bone portions.

In accordance with another aspect, a method of securing and stabilizinga plurality of bone portions is provided. The method includes connectinga trailing end portion of a cable to a bone plate, positioning the boneplate adjacent the bone portions, advancing a leading end portion of thecable around the bones to form a loop of the cable around the boneportions, and connecting the leading end portion of the cable to thebone plate. In one form, connecting the cable to the bone plate includesadvancing the leading end portion of the cable through an aperture ofthe bone plate sized so that there is a slip fit between the cable andthe bone plate. The method further includes tightening the loop of cablearound the bone portions to seat the bone plate against the boneportions. In one approach, tightening the loop of cable around the boneportions includes pulling the leading end portion of the cable away fromthe bone plate and urging the bone portions together. As the cable loopis tightened around the bone portions, the tension force acting alongthe surgical cable substantially simultaneously urges the bone portionstogether (if they are separated), draws the bone plate against the boneportions, and firmly seats the bone plate against the bone portions. Themethod further includes reconfiguring a locking device associated withthe bone plate to a locked configuration to fix the locking device tothe cable and secure the bone plate, cable, and bone portions to oneanother. In this manner, the method provides a rapid and straightforwardapproach for urging a plurality of bone portions together, seating abone plate against the bone portions, and securing the bone plate,cable, and bone portions to one another.

The method further includes driving bone anchors through openings in thebone plate and into the bone portions to rigidly fix the bone plate tothe bone portions. One advantage of using the cable to draw the boneplate against the bone portions and seat the bone plate against the boneportions is that the bone plate can be secured against the bone portionsusing the cable before the bone anchors are used to provide additionalfixation of the bone plate to the bone portions. This may reduceshifting of the bone plate on the bone portions while driving the boneanchors through the openings in the bone plate. Another advantage ofusing the cable to draw the bone plate against the bone portions andseat the bone plate against the bone portions is that the bone plate maybe firmly seated against the bone portions even if the bone portions areweakened, such as bones having a thin cortical section and/or voidsbetween cortical sections. This approach stands in contrast to someprior fixation systems that exclusively utilize bone screws to seat aplate member against bones. If the bones are weakened, the bone screwsof these prior fixation systems may not have sufficient purchase withthe bones to draw the bone plate against the bones and fully seat thebone plate.

In another aspect, a bone plate system is provided for stabilizingportions of one or more bones that provides an easier-to-use approachfor stabilizing the bone portions. The bone plate system includes a boneplate and a connector device having a flexible portion for being loopedaround the bone portions and secured to the bone plate. The bone platehas a deformable member with a throughbore configured to receive theconnector device extending therethrough. The deformable member hasexposed opposing crimp portions disposed across the throughbore from oneanother with the opposed crimp portions being configured to be deformedtoward each other to fix the connector device to the bone plate. Theexposed opposing crimp portions may thereby provide more secure anddurable locking of the connector device to the bone plate than someconventional approaches that utilize a single stud to pinch a wire orcable against a channel wall.

The deformable member may be a cylindrical, tubular member and the crimpportions may be diametrically opposed from one another across thethroughbore. The tubular member presents a less obtrusive profile thansome prior approaches that utilize outwardly projecting locking members.This reduces the likelihood of tissues becoming pinched by or otherwiseentangled with the features of the locking device.

In one form, the bone plate includes a pair of tool-receiving throughopenings on opposite sides of the deformable member. The tool-receivingthrough openings are sized to accommodate a user positioning a tool inthe through openings, such as advancing jaws of a crimping tool into thethrough openings. One of the opposing crimp portions of the deformablemember extend along one of the pair of bone plate through openings andthe other crimp portion extends along the other of the pair of throughopenings. In this manner, the crimp portions of the deformable memberare readily accessible to a tool advanced into the bone plate throughopenings so that the tool may be used to deform the deformable portions.

In another form, the bone plate includes a pair of elongated, spacedtool alignment members connected to the deformable member and extendinggenerally parallel to one another on opposite sides of the deformablemember. The tool alignment members define at least a portion of atool-receiving through opening of the bone plate. The tool alignmentmembers may be separated by a predetermined distance that is slightlylarger than a width of a jaw of a crimping tool to provide the jaw withclearance to be inserted into the tool-receiving through opening. Thiscooperating configuration also aligns the jaws of the crimping tool withthe crimp portions along the deformable member and ensures that the jawsof the crimping tool engage the crimp portions of the deformable member.

The bone plate system is especially advantageous for emergency reentrysituations wherein the chest cavity must be accessed after utilizing thebone plate system to secure halves of a cut sternum together. Emergentreentry situations may include situations where the patient suffers aheart attack after installation of the bone plate system. Because thecable is disposed within the throughbore of the bone plate deformablemember, cutting the deformable member cuts the deformable member and thecable in one step. This is especially advantageous when compared toprior systems with separate approximating wires and bone plates disposedalong the cut sternum which may require separate tools for cutting theapproximating wires and the bone plates. Separately cutting theapproximating wires and the bone plates of these prior systems mayincrease the time it takes to gain access to the chest cavity of thepatient in an emergent reentry situation.

In accordance with another aspect, an instrument for tensioning asurgical cable is provided. The tensioning device has a rotarytensioning device configured to have a cable wound thereon and a ratchetassembly that permits turning of the rotary tensioning device in a windup direction and selectively resists turning of the rotary tensioningdevice in a pay out direction. By wrapping the surgical cable about therotary tensioning device, the tensioning device can take up and tensiona relatively long section of surgical cable. This approach stands incontrast to some prior surgical cable tensioning instruments that, inorder to tension a cable, utilize a cable tensioning mechanism whichlinearly translates a cable locking mechanism secured to the cable. Withthese devices, the overall length of the device is directly proportionalto the length of linear travel of the tensioning mechanism such thattensioning larger sections of cable requires a proportionally largertensioning device.

The rotary tensioning device has gripping portions configured to shiftrelative to each other with turning of the rotary tensioning device.Specifically, turning the rotary tensioning device in the wind updirection shifts the rotary tensioning device form a pass throughconfiguration that permits the cable to be drawn through the grippingportions to a gripped configuration that fixes the cable relative to theshifted gripping portions. In this manner, tension can be applied to thefixed cable by simply turning the rotary tensioning device in the windup direction. Thus, the tensioning instrument provides an improvementover some conventional tensioning instruments that require a user toperform separate manual operations of locking the tensioning instrumentto the cable and then applying tension to the cable, such as by usingdifferent handles of the instrument to perform the locking andtensioning operations.

In one form, the ratchet assembly has a tensioning configuration thatpermits a surgeon to incrementally rotate the rotary tensioning devicein a wind up direction, wrap the cable about the rotary tensioningdevice, and apply tension to the cable. By permitting incrementaltensioning of the cable, the surgeon receives tactile feedback as thecable is tensioned and may stop rotating the rotary tensioning deviceonce the desired tension has been reached. At this point, the cable maybe secured, for example, in a looped configuration around a pair of boneportions using a locking device of a bone plate as described in greaterdetail below. With the cable secured, the ratchet assembly may bereconfigured to a release configuration to permit the rotary tensioningdevice to rotate in the pay out direction and allow the tensioningdevice to be removed from the surgical cable.

The ratchet assembly may include a drive for turning the rotarytensioning device and a release mechanism having a release configurationthat disengages the drive from the rotary tensioning device and atensioning configuration that engages the drive to the rotary tensioningdevice. With the release mechanism in the engaged configuration, thedrive is connected to the rotary drive device such that turning of thedrive produces turning of the rotary tensioning device. With the releasemechanism in the disengaged configuration, the rotary tensioning devicecan turn relative to the drive which allows the tensioning instrument tobe removed from the cable, such as by pulling the tensioning instrumentoff of the surgical cable. Pulling the tensioning instrument off of thesurgical cable turns the rotary tensioning device and causes the cableto be unwound from the rotary tensioning device. Further, because thedrive is disengaged from the rotary tensioning device, turning of therotary tensioning device due to unwinding of the cable therefromgenerally does not produce movement of the drive which makes thetensioning instrument easier to handle as it is removed from the cable.

In another aspect, a method is provided for approximating and securing aplurality of bone portions using a cable and a tensioning instrumentthat is configured to quickly and easily tension the cable around thebone portions. The method includes positioning a trailing end portion ofthe cable and a locking device connected thereto adjacent one or more ofthe plurality of bone portions and advancing a leading end portion ofthe cable around the plurality of bone portions and into the lockingdevice to form a loop of the cable around the bone portions. The methodincludes feeding the leading end portion of the cable through a distalend of the tensioning instrument, advancing the cable between grippingportions of a rotary tensioning device of the tensioning instrument, andoutward though a proximal end of the tensioning instrument. Next, thetensioning instrument is shifted downward along the cable until thedistal end of the tensioning instrument abuts the locking device. Theleading end portion of the cable is then pulled away from the lockingdevice to draw slack out of the cable.

The method further includes turning the rotary tensioning device tosubstantially simultaneously lock the rotary tensioning device to thecable and tension the cable. Turning the rotary tensioning device locksthe cable to the rotary tensioning device by reconfiguring the grippingportions of the rotary tensioning device from a pass-throughconfiguration that permits the cable to be advanced through the grippingportions to a gripped configuration which fixes the cable relative tothe shifted gripping portions. Further, turning the rotary tensioningdevice tensions the cable by drawing a portion of the cable on a distalside of the rotary tensioning device onto the rotary tensioning devicewhile the distal end of the tensioning instrument remains abutting thelocking device. If the bone portions are separated, turning of therotary tensioning device tensions the looped cable around the boneportions and approximates the bone portions together. The method furtherincludes selectively locking the rotary position of the rotarytensioning device once the cable has been sufficiently tensioned inorder to maintain the cable at the desired tension. The locking deviceof the cable may then be reconfigured to a locked configuration tosecure the tightened loop of cable around the bone portions. In oneform, turning the rotary tensioning device also draws a portion of thecable onto the rotary tensioning device from a proximal side of therotary tensioning device. The tensioning device preferably has aninterior cavity sized to accommodate relatively long lengths of cablebeing drawn onto the rotary tensioning device from both the distal andproximal sides of the rotary tensioning device. The method therebyprovides a quick and elegant approach to tensioning and securing a cablearound a plurality of bone portions and, in some applications,approximating the bone portions while tensioning the cable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a bone plate system in accordance withthe present invention positioned on a sternum that has been cutlongitudinally;

FIG. 2 is a perspective view of the bone plate system of FIG. 1 showingsurgical cables of the bone plate system having opposite ends of thesurgical cables connected to a plate member of the bone plate system;

FIG. 3 is a perspective view of the bone plate of the bone plate systemof FIG. 1 showing laterally spaced halves of the bone plate withthroughbores therein for receiving bone anchors;

FIG. 4 is a cross sectional view taken across line 4-4 in FIG. 3 showingthrough apertures of the bone plate at one end thereof;

FIG. 5 is an enlarged elevational view of the bone plate member of FIG.1 showing the through apertures of the bone plate shown in FIG. 4;

FIG. 6 is a perspective view of the surgical cables of the bone platesystem of FIG. 1 showing plugs of the surgical cables that abut surfacesof the through apertures of the bone plate and restrict the surgicalcables from passing through the apertures;

FIG. 7 is a cross sectional view taken across line 7-7 in FIG. 4 showingthreads of the throughbores disposed between the upper and lowersurfaces of the bone plate;

FIG. 8 is a side elevational view of the bone plate of FIG. 1 showinggenerally flat upper and lower surfaces of the bone plate;

FIGS. 9-16 illustrate a method of using the bone plate system of FIG. 1to secure the halves of the cut sternum;

FIGS. 16A-16D illustrate an alternative approach of using the bone platesystem of FIG. 1 to secure the halves of the cut sternum;

FIG. 17 is an elevational view of one of the bone screws of the boneplate system of FIG. 1 showing threads on both the head and shank of thebone screw;

FIG. 18 is a perspective view of the bone screw of FIG. 17 showingradially extending undercuts in the head of the bone screw for engaginga retention mechanism of a driver tool;

FIG. 18A is a perspective view of a driver tool showing a centering pinprojecting from a distal end of the tool for centering the tool on ascrew head;

FIG. 19 is a perspective view of another bone plate member having ageneral curvature of the bone plate along its length;

FIGS. 20 and 21 are elevational views of the bone plate of FIG. 19showing a generally convex upper surface of the bone plate and agenerally concave lower surface of the bone plate;

FIG. 22 is a perspective view of another plate member having a singlelocking device for locking a surgical cable to the bone plate;

FIG. 23 is a plan view of the bone plate of FIG. 22 with a surgicalcable having one end connected to the bone plate and an opposite endwith a hook disposed thereon for advancing around bones;

FIG. 24 is an enlarged perspective view of the bone plate and surgicalcable of FIG. 23 showing the end of the surgical cable connected to thebone plate;

FIG. 25 is a cross sectional view taken across line 25-25 in FIG. 22showing through apertures of the bone plate for receiving the surgicalcable;

FIGS. 26 and 27 are elevational views of the bone plate of FIG. 22showing a generally convex upper surface and a generally concave lowersurface of the bone plate;

FIG. 28 is a perspective view of another plate member showing a singlelocking device of the bone plate disposed at one end of the bone plate;

FIGS. 29-32 are views of another bone plate and screws for usetherewith;

FIG. 33 is an elevational view of the bone plate of FIG. 29 showing agenerally convex upper surface and a generally concave lower surface ofthe bone plate;

FIG. 34 is a perspective view of an alternative screw showing upstandingfeatures of the screw head for engaging a retention feature of a drivertool;

FIG. 35 is a plan view of another plate member having a single lockingdevice for locking a surgical cable to the bone plate

FIG. 36 is a perspective view of the bone plate of FIG. 35;

FIGS. 37 and 38 are elevational views of the bone plate of FIG. 36showing a generally convex upper surface of the bone plate and agenerally concave lower surface of the bone plate;

FIGS. 39 and 40 are perspective views of another cable tensioninginstrument showing a distal end into which a surgical cable may beadvanced and a proximal end with an outlet opening through which thesurgical cable is pulled outward therefrom;

FIG. 41 is an exploded perspective view of the tensioning device of FIG.39;

FIG. 41A is an enlarged end elevational view of a drive shaft of thetensioning instrument of FIG. 39;

FIG. 42 is a front perspective view of a tension drive of the tensioninginstrument of FIG. 39 showing a drive socket of the tension drive;

FIG. 43 is a rear perspective view of the tension drive of FIG. 42showing a recess for receiving a pin connected to a tension ring of thetensioning device of FIG. 39;

FIG. 44 is a perspective view of the tension ring of the tensioninginstrument of FIG. 39 showing a central opening of the tension ringwhich receives the tension drive;

FIG. 45 is an elevational view of the tensioning instrument of FIG. 39showing an outer profile of a body of the tensioning device;

FIG. 46 is a cross sectional view taken across line A-A in FIG. 45showing a distal end of the tensioning instrument abutting a lockingdevice and a simplified surgical cable extending through the tensioninginstrument to illustrate a path of the surgical cable from the lockingdevice through the tensioning instrument;

FIG. 47 is a cross sectional view similar to FIG. 46 showing thesurgical cable locked to a rotary tensioning device of the tensioninginstrument after a handle of the tensioning instrument has been turnedninety degrees;

FIG. 48 is an elevational view of the tensioning instrument of FIG. 39showing a cap welded to the body of the tensioning instrument to securecomponents of the tensioning instrument within the body;

FIG. 49 is a cross-sectional view taken across line B-B in FIG. 48showing a portion of the drive shaft received in the drive socket of thetension drive so that the drive shaft is in operative engagement withthe tension drive;

FIG. 50 is a cross sectional view similar to FIG. 49 showing the tensiondrive and the tension ring rotated after the handle connected to thedrive has been turned ninety degrees;

FIG. 51 is a cross sectional view similar to FIG. 50 showing a releasebutton of the handle pressed and a button shaft connected to the releasebutton disengaging the socket of the tension drive from the drive shaft;

FIG. 52 is a top plan view of the tensioning device showing openings ofthe tension drive and the tension ring aligned with the outlet openingof the body of the tensioning device when the handle is aligned with asurgical cable path through the tensioning device;

FIG. 53 is a perspective view of another cable tensioning instrument;

FIG. 54 is an exploded perspective view of the tensioning instrument ofFIG. 53;

FIG. 55 is a fragmentary view of components of the cable tensioninginstrument of FIG. 53 including a drive shaft and a ratchet assembly;

FIG. 56 is a partial cross-sectional view of a release shaft of thetensioning instrument disposed in the drive shaft;

FIG. 57 is a perspective view of a tension drive of the tensioninginstrument of FIG. 53 showing a socket that receives a drive portion ofthe drive shaft;

FIG. 58 is an elevational view of the tension drive of FIG. 57 showing alongitudinal groove formed in a face of the tension drive;

FIG. 59 is a plan view of the tension drive of FIG. 57 showing endplates of the tension drive that define a recess therebetween;

FIG. 60 is a perspective view of a clamp member that is received in therecess of the tension drive, FIG. 60 showing a face of the clamp memberand a groove formed therein;

FIG. 61 is a cross-sectional view taken across line 61-61 in FIG. 53showing the drive shaft connected to the socket of the tension drive anda head of the release shaft aligned with ball bearings in the driveshaft drive portion;

FIG. 62 is a cross-sectional view similar to FIG. 61 showing the releaseshaft head shifted out of alignment with the ball bearings which permitsthe ball bearings to shift inwardly and disengage the drive shaft fromthe tension drive;

FIG. 63 is a cross-sectional view taken across line 63-63 in FIG. 53 andshows a through passage of a body of the tensioning instrument that isaligned with a through opening formed between the tension drive and theclamp member;

FIG. 64 is an enlarged cross-sectional view similar to FIG. 63 showing aprotrusion of the clamp member disposed in a complementary recess of theinstrument body;

FIG. 65 is a cross-sectional view similar to FIG. 64 showing a handle ofthe instrument having been turned which moves the clamp memberprotrusion out of the body recess and into engagement with an innersurface of the body;

FIG. 66 is a perspective view of a bone anchor having a generallycross-shaped drive recess;

FIG. 67 is a plan view of the bone anchor of FIG. 66 showing features ofthe drive recess;

FIG. 68 is a perspective view of a distal end portion of a driver toolfor use with the bone anchor of FIG. 66; and

FIG. 69 is an elevational view of the distal end portion of the drivertool of FIG. 68 showing a distal tapered post of the driver tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, there is provided a bone plate system 10 forsecuring portions of one or more bones. In one approach, the bone platesystem 10 is used to secure a sternum 12 that has been cut 14 intohalves 16, 18 with the cut 14 extending longitudinally along the sternum12. The bone plate system 10 includes a bone plate, such as plate member20, and surgical cables 22, 24 configured to be advanced around thesternal halves 16, 18 and form loops 23, 25 (see FIG. 2) about thesternal halves 16, 18. Each surgical cable 22, 24 has a trailing endportion 26 connected to the bone plate 20 and a leading end portion 28configured to be advanced around the sternal halves 16, 18 and intoopenings 30, 32 of the bone plate 20. The openings 30, 32 are sized toform a slip fit between the bone plate 20 and the surgical cables 22,24. To tighten the loops of the cables 22, 24 about the sternal halves16, 18, the bone plate 20 is held adjacent the sternal halves 16, 18 andthe leading end portions 28 of the surgical cables 22, 24 are advancedin directions 33, 35. As the surgical cables 22, 24 tighten around thesternal halves 16, 18, the tension forces in the surgical cables 22, 24urge the sternal halves 16, 18 together, draw the bone plate 20 againstthe sternal halves 16, 18, and firmly seat the bone plate 20 against thesternal halves 16, 18. The bone plate system 10 thereby allows rapid andsubstantially simultaneous approximation of the sternal halves 16, 18,drawing of the bone plate 20 toward the sternal halves 16, 18, andseating the bone plate 20 against the sternal halves 16, 18 as thesurgical cables 22, 24 are tensioned about the sternal halves 16, 18.

The bone plate system 10 has a pair of locking devices 40, 41 disposedat opposite ends of the bone plate 20 for fixing the bone plate 20 tothe surgical cables 22, 24. As discussed in greater detail below, afterthe leading end portions 28 of the surgical cables 22, 24 have beenadvanced through openings 30, 32 of the bone plate 20 and properlytensioned, the locking devices 40, 41 are reconfigured to a lockedconfiguration to fix the bone plate 20 to the surgical cables 22, 24.The surgical cables 22, 24 have high tensile strength and, once loopedaround the sternal halves 16, 18 and fixed to the bone plate 20, serveas a primary load bearing mechanism that resists separation and relativemovement of the sternal halves 16, 18. Thus, the bone plate system 10provides a straightforward and easy-to-use apparatus for forming asecure construct of the sternal halves 16, 18, bone plate member 20, andsurgical cables 22, 24.

The bone plate 20 has a body 42 extending along the length of the boneplate 20 between the locking devices 40, 41 that includes a plurality ofthroughbores 44 for receiving bone anchors, such as bone screws 46. Thebone screws 46 are driven into the throughbores 44 and sternum 12 to fixthe bone plate 20 to both halves 16, 18 of the sternum 12. With the bonescrews 46 fully driven into the sternal halves 16, 18, the bone screws46 provide anchor points to transmit loading from the sternal halves 16,18 to the bone plate 20 and reinforce the sternum 12. In this manner,the bone plate system 10 utilizes the high tensile strength of thesurgical cables 22, 24 extending tightly about the bone plate 20 as aprimary load bearing mechanism and the rigid engagement between thescrews 46 and the bone plate 20 as a secondary load bearing mechanism toresist to relative movement of the sternal halves 16, 18. By utilizingboth load bearing mechanisms, the bone plate system 10 provides for loadbearing between the primary load bearing cables 22, 24 and the secondaryload bearing screws 46 with greater post-operative stability andfixation of the sternal halves 16, 18 than either load bearing mechanismon its own. As will be apparent, the bone plate system 10 may be used tosecure and stabilize many different types of bones, bone fragments, andportions of bones. The bone plate system 10 may also be used to hold oneor more medical implant devices, such as a splint, rod, graft, or thelike, against one or more bones.

With respect to FIG. 2, the bone plate 20 has a pair of tool alignmentmembers, such as longitudinal members 50, 52, positioned on oppositeside of the cut 14 (see FIG. 1) that extend along the length of the boneplate 20. Transverse supports 54, 56, 58 extend across the cut 14between the longitudinal members 50, 52 and serve to interconnect andbrace the longitudinal members 50, 52. The transverse supports 54, 56,58 rigidly restrict lateral, rostral caudal, and anterior posteriormovement of the longitudinal members 50, 52 and the sternal halves 16,18 secured thereto.

With reference to the longitudinal member 50 as shown in FIG. 3, each ofthe longitudinal members 50, 52 have portions 49A, 49B projecting beyondthe transverse supports 54, 58 and along the sternal half 16 to increasethe contact area between the bone plate 20 and the sternal half 16 alongthe cut 14 and further secure the bone plate 20 to the sternal half 16.The projecting portions 49A, 49B also serve to guide one of the jaws152, 153 of a crimping tool 150 (see FIG. 14B) into an aligned positionwith the locking devices 40, 41, as will be discussed in greater detailbelow. Extending inward toward the center of the bone plate 20 are innerguide portions 51A, 51B of the longitudinal members 50, 52. The innerguide portions 51A, 51B serve to guide the other one of the jaws 152,153 of the crimping tool 150 into an aligned position on the oppositeside of the locking devices 40, 41. The longitudinal members 50, 52further have angled portions 53A, 53B that bow outward from the innerguide portions 51A, 51B to laterally space halves of the bone plate 20,such as generally triangular lobes 55, outward from a central,longitudinal axis 106 of the bone plate 50. The lobes 55 havethroughbores 44 formed therein such that positioning the lobes 55outward from the longitudinal axis 106 positions longitudinal axes 57(see FIG. 17) of the bone screws 46 away from the cut 14. This improvesthe engagement between the bone screws 46 and the sternal half 16 bykeeping the bone screws 46 from splintering the bone adjacent the cut14.

With reference to FIGS. 2-4, the bone plate system 10 includesconnections 64, 66 between the trailing ends 26 of the surgical cables22, 24 and the bone plate 20. The connections 64, 66 are similar and, asshown with respect to connection 66 and cable 24, each have a stopaperture 70 of the bone plate 20 sized to permit the leading end portion28 of the surgical cable 24 to be advanced therethrough until an endplug 72 (see FIG. 6) of the trailing end portion 26 of the cable 24enters the stop aperture 70 and abuts against an interior shoulder orannular surface 74 of the bone plate 20. As shown in FIG. 4, the stopaperture 70 includes a larger diameter portion 76 sized to permit thesurgical cable 24 and the end plug 72 thereof to travel through thelarger diameter portion 76 and abut the annular surface 74. The stopaperture 70 also has a smaller diameter portion 78 that includes theannular surface 74 and is configured to restrict the end plug 72 fromadvancing out of the stop aperture 70 in direction 62. The end plug 72may be swedged onto the braided multi-stranded wires of the cable 24 orsecured using, for example, welding. In an alternative form, theconnections 64, 66 may have, for example, a press fit or weld betweenthe trailing end portions 26 of the surgical cables 24, 26 and the boneplate 20.

As shown in FIGS. 4 and 5, the annular surface 74 of the stop aperture70 narrows the stop aperture 70 to block the movement of end plug 72beyond the annular surface 74. At this point, the trailing end 26 of thesurgical cable 24 can no longer be moved in direction 62 beyond the stopsurface 74. Utilizing the abutting contact between the end plug 72 andthe annular surface 74 provides an easy to use approach for connectingthe trailing end 26 of the surgical cable 24 to the bone plate 20. Thebone plate 20 and surgical cables 22, 24 may be assembled in anoperating room by first selecting surgical cables 22, 24 suitable for aparticular patient anatomy and then advancing the leading end portions28 of the selected surgical cables 22, 24 through the stop aperture 70of the bone plate 20. In another approach, the bone plate 20 andpreselected surgical cables 22, 24 may be packaged in a preassembledconfiguration to save assembly time in the operating room.

In one form, the transverse support 58 has a tubular wall 82 with aninner surface 84 thereof defining a locking aperture 80 as shown in FIG.4. The tubular wall 82 includes exposed crimp portions 85, 85 onopposite sides of the aperture 80 configured to be deformed toward eachother and fix the cable 28 to the bone plate 20. The locking aperture 80extends between opposite lateral surfaces 86, 88 of the bone plate 20and is configured to receive the leading end portion 28 of the surgicalcable 24. To increase the ease with which the leading end portion 28 ofthe surgical cable 24 may be advanced into the locking aperture 80, thebone plate 20 may include a chamfered surface 90 adjacent the openingsof the aperture 70. Further, the tubular wall 82 may have a generallyconstant diameter along its length. In one form, the tubular wall 82 isfree of any openings in communication with the locking aperture 84 whichreduces the likelihood of tissues entering the aperture 84. This mayalso increase the strength of the tubular wall 82. Still further, thelocking devices 40, 41 may be integral with the bone plate 20 and have aportion of the transverse supports 54, 58.

The locking aperture 80 is preferably sized with a diameter slightlylarger than the surgical cable 24 such that the inner surface 84 of thetubular wall 82 is initially in a slip fit configuration with thesurgical cable 24. The locking aperture 80 is also sized to provide acompression fit between the inner surface 84 of the tubular wall 82 andthe surgical cable 24 to maintain the positioning of the tubular wall 84along the surgical cable 24 once the tubular wall 82 has been crimped.Using a surgical cable 24 having a diameter of about 0.049 inches as anexample, the outer diameter of the tubular wall 82 is initially about0.096 inches and the diameter of the locking aperture 80 may be about0.055 inches. Crimping the tubular wall 82 against the surgical cable 24flattens out the tubular wall 82, decreases the diameter of the lockingaperture 80 by about 0.01 inches, and forms a compression fit betweenthe inner surface 84 of the tubular wall 82 and the surgical cable 24.

Rather than utilizing stop apertures 70 to connect one end of thesurgical cables 22, 24 to the bone plate 20 and a locking aperture 80 toconnect the other end of the surgical cables 22, 24 to the bone plate20, the locking devices 40, 41 may have multiple lumen crimps with aseparate lumen for crimping each end of the cables 22, 24. In otherforms, the locking devices 40, 41 may be separate from the bone plate20. For example, the bone plate 20 may have apertures for receiving thesurgical cables 22, 24 but a separate and distinct crimp may be appliedto each of the surgical cables 22, 24 to fix the cables 22, 24 in theclosed loop configuration about the sternal halves 16, 18 after thesurgical cables 22, 24 have been advanced through the apertures of thebone plate. Examples of separate and distinct crimps that could be usedwith such a plate member include the multiple lumen crimps disclosed inU.S. Pat. Nos. 6,832,532 and 6,629,975.

With reference to FIG. 7, the throughbores 44 of the bone plate 20 haveretention devices, such as threads 100, configured for engaging threads184 on the heads 181 of the bone screws 46 (see FIG. 17) and resistingback-out of the screws 46 from the throughbores 44. The threads 100 ofeach throughbore 44 are spaced inward from the upper and lower surfaces102, 104 of the bone plate 20 along a bore axis 108 by equal distances.With reference to FIG. 8, the upper and lower surfaces 102, 104 of thebone plate 20 are generally straight and permit either the upper andlower surface 102, 104 to be placed against sternal halves 16, 18. Bypositioning the threads 100 inward from the upper and lower surfaces102, 104 equal distances, the threads 184 of the bone screw 46 canengage the threads 100 of the aperture 44 regardless of whether theupper surface 102 or the lower surface 104 is facing the sternal halves16, 18.

The threads 100 include a plurality of leads adjacent the upper andlower surfaces 102, 103 of the bone plate 20, such as leads 105, 107adjacent the upper surface 102 and leads 109, 111 adjacent the lowersurface 104. The head 181 of the bone screw 46 has threads 184 with amatching number of leads 186, 188 (see FIG. 17) that are adapted to matewith the leads 105, 107 or 109, 111 of the throughbore 44 depending onwhich direction the bone screw 46 is driven into the throughbore 44. Forexample, with reference to FIG. 7, with the lower surface 104 of thebone plate 20 positioned against the sternal halves 16, 18, a surgeoncan drive the bone screw 46 from above the upper surface 102 into one ofthe throughbores 44 until the head 181 of the bone screw 46 is proximalthe threads 100 of the throughbore 44. Rotation of the bone screw 46brings the leads 186, 188 of the head 181 into engagement with the leads105, 107 of the throughbore 44. Conversely, if the upper surface 102 ofthe bone plate 20 is positioned against the sternal halves 16, 18, thebone screw 46 would be driven from above the lower surface 104 into thethroughbore 44 and the leads 186, 188 of the head 181 would engage theleads 109, 111 of the throughbore 44. In this manner, the bone screws 46can be driven into the throughbores 44 and rotated to bring the leads186, 188 into engagement with either of the leads 105, 107 or 109, 111of the throughbore 44 regardless of whether the upper surface 102 or thelower surface 104 of the bone plate 20 is positioned against the sternalhalves 16, 18. Although only two leads (either 105, 107 or 109, 111depending on the orientation of the bone plate 20) are identified asengaging the leads 186, 188 of the screw head 181, the threads 100 ofthe throughbore 44 and the threads 184 of the head 181 each have fourleads configured so that the threads 184 engage the threads 100 with aquarter-turn or less of the screw 46. Preferably, the number of leads ofthe throughbore threads 100 and the number of leads of the screw headthreads 184 match so that all of the leads of the throughbore threads100 engage all of the leads of the screw head threads 184 as the bonescrew 46 is driven into the throughbore 44.

With respect to FIGS. 9-16, a method is disclosed for utilizing the boneplate system 10 to secure the halves 16, 18 of a cut sternum 12. Thetrailing end 26 of each cable 22, 24 may be connected to the bone plate20 as discussed above and the bone plate 20 may be positioned above thesternal halves 16, 18. The leading end portion 28 of each cable 22, 24is advanced around the sternal halves 16, 18 and into the lockingaperture 80 adjacent lateral surface 86 (see FIG. 4). The leading endportion 28 is advanced outward from the locking aperture 80 adjacent theopposite lateral surface 88 in direction 120, as shown in FIG. 10.

With the leading end 28 of each surgical cable 22, 24 extending beyondthe lateral surface 88 of the bone plate 20, the bone plate 20 is heldagainst the sternal halves 16, 18 and a tensioning instrument 122 (seeFIG. 11) is used to apply tension to the surgical cables 22, 24 and drawthe bone plate 20 against the sternal halves 16, 18. More specifically,the leading end portion 28 of the surgical cable 24 is advanced througha distal end 124 of the tensioning instrument 122 until the leading end28 advances outward from a proximal end 126 of the tensioning instrument122, as shown in FIG. 12. The leading end 28 of the surgical cable 24may be grasped and pulled in direction 130 and the tensioning instrument122 slid downward along the surgical cable 24 in direction 132 until thedistal end 124 thereof abuts the lateral surface 88 of the bone plate.The handle 136 of the tensioning instrument 122 is rotated in direction138 which causes a rotary tensioning device 139 of the tensioninginstrument 122 to lock onto the surgical cable 24 and shift the surgicalcable 24 in direction 130. A ratchet assembly 140 of the tensioninginstrument 122 restricts return of the surgical cable 24 in direction142 once tension has been applied to the surgical cable 24 by way ofrotation of the handle 136. Continued rotation of the handle 136advances the surgical cable 28 in direction 130, tightens the surgicalcable 24 around the sternal halves 16, 18, and compresses the sternalhalves 16, 18 together. Further, tensioning the surgical cable 24 drawsthe bone plate 20 downward against the sternal halves 16, 18 and seatsthe bone plate 20 securely against the compressed sternal halves 16, 18.In one approach, forceps are used in conjunction with tensioning of thesurgical cable 24 to bring the sternal halves 16, 18 together.

Once the desired amount of tension has been applied to the surgicalcable 24, the crimping tool 150 is used to clamp the tubular wall 82 oftransverse support 58 to the surgical cable 24. The crimping tool 150has jaws 152, 153 for being positioned on opposite sides of the tubularwall 82 with jaw surfaces 157, 159 positioned adjacent crimp portions ofthe tubular wall 82, such as the portions 161, 163 shown in dashed linesin FIG. 14B. To permit access to the crimp portions 161, 163, the boneplate 20 has access openings, such as through openings 143, 145, sizedto permit the jaws 152, 153 to be inserted therein. The through openings143, 145 have alignment walls, such as walls 147A, 147B and 149A, 149Bextending away from the tubular wall 82 on opposite sides of the throughopenings 143, 145. The jaws 152, 153 have a width 154 sized to fitsnugly between the walls 147A, 147B and 149A, 149B and into position onopposite sides of the tubular wall 82. More specifically, the width 154of the jaws 152, 153 is less than a distance 156A between the walls147A, 147B and a distance 156B between the walls 149A, 149. The closetolerances between the jaws 152, 153 and the walls 147A, 147B and 149A,149B ensures that the jaw surfaces 157, 159 are aligned with the crimpportions 161, 163 before the crimping tool 150 crimps the tubular wall82. For example, the distances 156A, 156B are about 0.21 inches, thewidth 154 of the jaws 152, 153 are about 0.2 inches, and the crimpportions 161, 163 extend along the tubular member 82 a distance 165 ofabout 0.140 inches.

Next, handles 160, 162 of the crimping tool 150 are squeezed together toshift the jaws 152, 153 against the crimp portions 161, 163, deform thecrimp portions 161, 163 toward each other, and crimp the tubular wall 82to the surgical cable 24. Once the tubular wall 82 has been crimped ontothe surgical cable 24, the crimping tool 150 can be removed and thetensioning instrument 122 may be removed by depressing a ratchet releasebutton 164 thereof and sliding the tensioning tool 122 along thesurgical cable 24 in direction 166 (see FIG. 14). Using a cable cutter170, the leading end portion 28 is then cut flush with the lateralsurface 88 of the bone plate 20. The process of tensioning and crimpingis repeated with the surgical cable 22. In some applications, thecrimping tool 150 may be configured to require a particular amount oftravel of the jaws 152, 153 towards one another before the crimping tool150 may be disengaged from the tubular wall 82. This configurationensures that the tubular wall 82 has deformed a predetermined distanceinto engagement with the surgical cable 24 and achieved a sufficientcrimp strength therewith before the surgeon can remove the crimping tool150.

With the surgical cables 22, 24 tensioned and crimped to the bone plate20, the bone screws 46 may be connected to a driver tool 180 (see FIG.18A) and driven into throughbores 44 of the bone plate 20 to secure thebone plate 20 to the sternal halves 16, 18, as shown in FIG. 16.

In an alternative approach shown in FIGS. 16A-D, the bone screws 46 maybe used to secure the bone plate 20 to one of the sternal halves 16, 18,such as sternal half 18 as shown in FIG. 16A. Next, the sternal halves16, 18 are approximated together using forceps, wire, or anotherapproach, as shown in FIG. 16B. With the sternal halves 16, 18approximated, bone screws 46 are driven into the throughbores 44 of thebone plate 20 disposed above sternal half 16, as shown in FIG. 16C.Next, the distal end portions 26 of the surgical cables 22, 24 areconnected to the bone plate 20 and the leading end portions 28 of thesurgical cables 22, 24 are looped around the sternal halves 16, 18 andinto openings 30, 32 of the bone plate 20, as shown in FIG. 16D. Thesurgical cables 22, 24 are then tensioned and locked to the bone plateas described above. Although the surgical cables 22, 24 are connected tothe bone plate 20 after the bone screws 46 have secured the bone plate20 to the sternal halves 16, 18, the surgical cables 22, 24 may stillact as a primary load bearing mechanism to resist movement of thesternal halves 16, 18.

In yet another approach, the sternal halves 16, 18 may be approximatedtogether using forceps, wires, or another approach before placing thebone plate 20 on the approximated sternal halves 16, 18, looping thesurgical cables 22, 24 around the sternal halves 16, 18, tensioning thesurgical cables 22, 24, locking the bone plate 20 to the surgical cables22, 24, and driving the bone screws 46 into the throughbores 44 of thebone plate 20 to fix the bone plate 20 to the sternal halves 16, 18.This approach is similar to the method described above with respect toFIGS. 9-16, with the exception that the forceps or wires are used toapproximate the sternal halves rather than the surgical cables 22, 24.

With reference to FIGS. 17 and 18, an elevational view of one of thebone screws 46 is shown. The bone screw 46 has a head 181 having drivestructures 182 for receiving a distal end of the driving tool 180. Thedrive structures 182 have undercuts 192 and radially extending members194 for engaging corresponding a screw retention feature on the drivingtool 180, such as a centering pin 198 of the driving tool 180. Advancingthe centering pin 198 into a blind bore 196 of the screw head 181centers the distal end of the driving tool 180 on the screw head 181 andcauses the centering pin 198 to resiliently deflect the radiallyextending members 194 downward. This produces a friction fit between thecentering pin 198 and the radially extending members 194 which keeps thescrew 46 retained on the distal end of the driving tool 180 beforedriving the screw 46 into bone.

The head 181 also includes threads 184 that include multiple leads 186,188 for engaging the multiple lead threads 100 of the throughbore 44.The threads 184 provide tactile feedback to the surgeon driving the bonescrew 46 into bone that the head 181 is engaged with the bone plate 20.Further, the threads 184 provide resistance to the bone screw 46 backingout of the throughbore 44 of the bone plate 20. As shown in FIG. 17, thescrew 46 has an elongate shank 190 with threads 192 thereon that mayhave a different pitch, size, and number of leads than the threads 184of the head 181. In one form, the shank 190 is configured to beself-drilling and self-tapping.

The surgical cables 22, 24 are made of surgical grade braidedmulti-stranded stainless steel cable. Other materials such as titaniumalloy, cobalt chromium alloy, polymers, or other biocompatible materialsmay also be used. The braided surgical cables 22, 24 have asignificantly higher tensile strength than surgical wires and providebetter resistance to separation and relative movement of the sternalhalves 16, 18. In one form, the cables 22, 24 have a diameter in therange of about 0.8 mm to about 2.4 mm, and more preferably about 1.3 mm.The cables 22, 24 may be swedged to reduce surface roughness and mayhave a high flexibility which may provide a tighter loop yet avoiddamage to surrounding tissue. The bone plate 20 may be fabricated from asurgical grade stainless steel, titanium, titanium alloy, cobaltchromium alloy, nitinol, polyether ether ketone, or other biocompatiblematerials. Likewise, the bone screws 46 may be made of, for example,stainless steel, titanium, titanium alloy, or cobalt chromium alloy. Thecomponents of the cable tensioner 122 may be made of metals or alloysincluding stainless steel.

Referring now to FIGS. 19-21, there is illustrated another embodiment ofa plate member 200 in accordance with the present invention. The boneplate 200 is generally the same as plate member 20 described above withrespect to FIGS. 1-8, with the exception of a curvature of the boneplate about at longitudinal axis 202 thereof.

More particularly, the bone plate 200 has a central portion 204 alignedalong the longitudinal axis 202 and locking devices 206, 208 alsoaligned along the longitudinal axis 202 on opposite sides of the centralportion 204. The bone plate 200 has curved plate halves 210, 212 thatare shaped to conform to bones having either a convex or concave outersurface. More specifically, if the bones (such as sternal halves 16, 18)have a convex outer surface, a concave lower surface 214 (see FIG. 21)of the bone plate 200 would be positioned against the outer surfaces ofthe bones. However, if the bones had a concave outer surface, a convexupper surface 216 of the bone plate 200 would be positioned against thebones. In this manner, the bone plate 200 can be flipped to positioneither the concave lower surface 214 or the convex upper surface 216against the bones to be secured depending on the anatomy of the patient.This provides greater flexibility and the ability to utilize a singleplate member 200 for two different anatomies.

With reference to FIGS. 22-27, another embodiment of a plate member 300is shown. The bone plate 300 is similar to the bone plates 20, 200except that the bone plate 300 has a single locking device disposed on acentral portion 304 of the bone plate 300. Further, like the bone plate200, the bone plate 300 has a curvature about a longitudinal axis 306thereof such that the bone plate 300 has a convex upper surface 307 anda concave lower surface 309, as shown in FIGS. 26 and 27.

Like the locking devices 40, 41 of the bone plate 20, the locking device302 includes a stop aperture 310, a locking aperture 312, a transversesupport 314, and a tubular wall 316. The stop aperture 310 is sized topermit a surgical cable 320 (see FIG. 23) to be advanced therethroughand form a connection 322 between and annular stop surface 324 of thestop aperture 310 and a plug 326 of the cable 320 (see FIG. 24). Withreference to FIG. 23, the surgical cable 320 may include a hardenedintegrated lead 330 and a hook 332 releasably connected thereto. Thehook 332 may be used for advancing a leading end 319 of the surgicalcable 320 around bones, such as the sternal halves 16, 18 of the sternum12. Once the leading end 319 has been advanced around the bones, thehook 332 may be pulled off of the integrated lead 330 and then theintegrated lead 330 may be advanced through the locking aperture 312.The locking device 302 of the bone plate 300 may then be reconfigured toa locked configuration as explained above with respect to locking device40.

Referring now to FIGS. 28 and 29, there is illustrated anotherembodiment of a plate member 400. The bone plate 400 is similar to thebone plates discussed above, except that the bone plate 400 has a singlelocking device 402 positioned at one end 404 of the bone plate 400opposite a transverse support portion 406 of the bone plate 400 along alongitudinal axis 407 of the bone plate 400. The bone plate 400 allows asurgical cable, such as surgical cable 24, to be offset from lobes 408of the bone plate 400.

With respect to FIGS. 29-33, another bone plate system 500 is shown. Thebone plate system 500 is similar in a number of ways to the foregoingbone plate systems in that the bone plate system 500 includes a platemember 502 having throughbores 504 therein for receiving bone anchors,such as bone screws 506, to secure the bone plate 502 to one or morebones. Further, the bone plate 502 may have a convex upper surface 508and a concave lower surface 510 that conform to the outer surfaces ofthe one or more bones. Further, the bone plate throughbore 504 hasthreads 512 including multiple leads 514 for engaging similar threads ona head 516 of the bone anchor 506. The bone plate system 500 isdifferent from the bone plate system 10 in that the bone plate system500 lacks a locking device for securing a surgical cable to the boneplate 500. However, the bone plate system 500 may be used in conjunctionwith a surgical wire, locking device, and/or the other bone platesystems discussed above.

An alternative embodiment of a bone screw head 600 is illustrated inFIG. 34. The head 600 includes upstanding, resilient members 602 thatdeform radially outward with connection of a driver tool to the head600. For example, advancing the centering pin 198 of the driving tool180 into a blind bore 604 of the screw head 600 causes the centering pin198 to deflect the upstanding members 602 radially outward. Deformingthe upstanding members 602 radially outward causes the upstandingmembers 602 to bias against the centering pin 198 and form a frictionfit therewith which retains the head 600 on the driving tool.

Referring now to FIGS. 36-38, there is illustrated another embodiment ofa plate member 700. The bone plate 700 is similar to the bone plate 300and includes only one locking device 702 disposed at a mid-point of thebone plate 700 along longitudinal axis 704. The bone plate 700 is alsosimilar to the bone plate 300 in that the bone plate 700 is curvedslightly about the longitudinal axis 704 such that the bone plate 700has a convex upper surface 710 and a concave lower surface 712 whichpermit the bone plate 700 to be flipped to position either the uppersurface 710 or the lower surface 712 against the bones depending onwhether the bones have a concave or convex outer surface. The bone plate700 differs from the bone plate 300 in that the bone plate 700 has asubstantially rectangular configuration with only one lobe 706 disposedat each of the outermost corners of the bone plate 700 and transversesupports 708 extending across the axis 704 which connect the lobes 706.The more rectangular configuration of the bone plate 700 may bepreferred when a plate member having a more compact footprint is desireddue to patient anatomy.

Turning to FIGS. 39-51, a tensioning instrument 800 is shown that issimilar to the tensioning instrument 122 and may be operated in a mannersimilar to the approach described above with respect to FIGS. 11-14.More specifically, the tensioning instrument 800 has a distal end 802with an inlet opening 804 sized to permit a surgical cable 805 to beadvanced through the inlet opening 804, into a body 808 of thetensioning instrument 800, and through a through opening 807 of a rotarytensioning device 824 within the body 808, as shown in FIG. 46. Thesurgical cable 805 is advanced in direction 806 until the surgical cable805 exits the tensioning instrument 800 through an outlet opening 810 ata proximal end 812 of the tensioning instrument 800. With the surgicalcable 805 extending outward from the outlet opening 810, a surgeon maymove the tensioning instrument 800 along the surgical cable 805 towardthe bone plate 20 with one hand and pull any slack out of the surgicalcable 805 with the other hand (see FIGS. 12, 13, and 39). The tensioninginstrument 800 has a drive 823 including a handle 820 that is configuredto be turned in a wind up direction 970 to rotate the rotary tensioningdevice 824 within the body 808 and cause the surgical cable 805 to bewound up onto the rotary tensioning device 824, as shown in FIG. 47. Thetensioning instrument 800 also has a ratchet assembly 826 thatselectively restricts rotation of the rotary tensioning device 824 in apay out direction while permitting a user to incrementally wind thesurgical cable 805 onto the rotary tensioning device 824 in the wind updirection 970 (see FIGS. 39 and 46).

Once a desired amount of tension has been applied to the surgical cableby rotating the drive 823 and the rotary tensioning device 824 connectedthereto, a release button 840 of a release mechanism 842 is pressed todisengage the ratchet assembly 826, permit the rotary tensioning device824 to turn freely in the pay out direction, and allow the tensioninginstrument 800 to be pulled off of the surgical cable 805 (see FIGS. 39,50, and 51). Disengaging the ratchet assembly 826 disconnects the rotarytensioning device 824 from the drive 823 and allows the surgical cable805 to be unwound from the rotary tensioning device 824, such as bypulling the surgical cable 805 outward from the distal end 802, withoutrotating the handle 820. In this manner, the tensioning instrument 800can be removed from the surgical cable 805 without the handle 820spinning or otherwise interfering with surgery.

With reference to FIG. 41, the drive 823 includes a drive shaft 850having a hex drive 852 for non-rotatably mating with a hex recess 854 ofthe handle 820 and threads 856 for engaging a shaft nut 858 which fixesthe drive shaft 850 to the handle 820. The tensioning instrument 800 hasa rotary tensioning device 824 with gripping portions, such as tensiondrive 872 and tensioning ring 932, which are configured to shiftrelative to each other and fix a cable to the rotary tensioning device824. With the drive shaft 850 operatively engaged with a tension drive872 of the rotary tensioning device 824, turning the handle 820 turnsthe drive shaft 850 and the tension drive 872 connected thereto,reconfigures the tension drive 872 and the tension ring 932 from apass-through configuration to a gripping configuration, and draws thesurgical cable 805 onto the tension ring 932 carried on the tensiondrive 872. The direct mechanical connection between the handle 820, thedrive shaft 850, and the tension drive 872 provides direct tactilefeedback of the tension being applied to the surgical cable 805.Further, the handle 820 has an overall length 851 that is twice acable-receiving diameter 853 of the tension ring 932, as shown in FIG.49. This two-to-one relationship balances the ease of turning the handle820 with providing sufficient tactile feedback regarding the tension inthe surgical cable 805, which are both important considerations whentensioning a surgical cable to a particular tension. Although atwo-to-one relationship is ideal for many applications, it will beappreciated that ½ to 1, 3 to 1, or other relationships may be desiredfor other applications. The tensioning instrument 800 also has a sleevebearing 862 that supports the drive shaft 850 and handle 820 as thehandle 820 is turned.

The tensioning instrument 800 includes structures that align throughapertures of the internal components of the tensioning instrument 800and increase the ease with which the surgical cable 805 can be advancedthrough the tensioning instrument 800 when the handle 820 is generallyaligned with the path of the surgical cable 805 through the body 808 ofthe tensioning instrument 800, as shown in FIG. 46. More specifically,the through opening 807 of the rotary tensioning device 824 includes apair of apertures 1014, 1016 of the tension ring 932 and a throughopening 1018 of the tension drive 872 that are aligned when the tensionring 932 and the tension drive 872 are in the pass-throughconfiguration, as shown in FIGS. 42, 44, and 46. To ensure that thetension drive through opening 1018 is oriented to permit the surgicalcable 805 to be advanced therethrough, the drive shaft 850 has agenerally rectangular oblong key 870 at one end thereof for engaging thetension drive 872, as shown in FIGS. 41 and 41A. The tension drive 872has a complementary generally rectangular oblong drive socket 874 (seeFIG. 42) for transmitting torque from the handle 820 and drive shaft 850to the tension drive 872 and the tension ring 932 carried thereon. Theoblong drive socket 874 includes spaced, generally flat sidewalls 876,878 in a vertical orientation (as shown in FIG. 42) parallel with athrough opening 1018 of the tension drive 874 through which the surgicalcable 805 is advanced. The socket 874 also has shorter sidewalls 879,891 in a horizontal orientation perpendicular to the through opening1018. Because the key 870 and the socket 874 are both oblong, the key870 and the socket 874 fit together in only two orientations that are180° apart from each other. In either orientation, the handle 820 isaligned with the through opening 1018 of the tension drive 872 when thedrive shaft key 870 is engaged with the tension drive socket 874. Thus,when the drive shaft 850 is engaged with the tension drive 872 and thehandle 820 is in a vertical orientation (see FIG. 46), the throughopening 1018 of the tension drive 872 will be aligned with the path ofthe surgical cable 805 through the body 808. As discussed in greaterdetail below, the tensioning instrument 800 has a bias assembly 946 thatmaintains the tension ring 932 in a pass-through position about thetension drive 872 where the tension ring apertures 1014, 1016 arealigned with the tension drive through opening 1018. In this manner, thesurgical cable 805 can be quickly and easily advanced through thetension ring apertures 1014, 1016 and the tension drive through opening1018 when the handle 820 is aligned with the path of the surgical cable805 through the tensioning instrument 800.

The drive shaft 850 also has a ratchet portion 882 with ratchet teethconfigured to engage a pawl 884 and restrict rotation of the drive shaft850 in a pay out direction, as shown in FIGS. 41 and 49. The pawl 884 isdisposed within an opening 892 of the body 808 and is aligned with theratchet portion 882 of the drive shaft 850 when the drive shaft 850 hasbeen inserted into a cavity 886 of the body and secured to the handle820. With reference to FIG. 41, the tensioning instrument 800 includes aplug 890 welded or otherwise secured to the body 808 to close theopening 892 and restrict removal of the pawl 884 from within the opening892. The opening 892 is sized to permit up and down movement of the pawl884 and a spring 894 is positioned between the plug 890 and the pawl 884to bias the pawl 884 downwardly into engagement with the teeth of theratchet portion 882 of the drive shaft 850. The pawl 884 has a tooth 898at a leading end thereof for engaging and restricting rotation of theteeth of the ratchet portion 882 when the drive shaft 850 is rotated ina pay out direction 971 and permitting rotation of the teeth of theratchet portion 882 when the drive shaft 850 is rotated in the wind updirection 970 (see FIG. 47). In one form, the plug 890 has an downwardlyextending fin that engages a slot on a trailing end 896 of the pawl 884.The fin restricts rotation of the pawl 884 relative to the plug 890 andkeeps the tooth 898 of the pawl 884 aligned with the teeth of theratchet portion 882.

To disengage the tension drive 872 from the drive shaft 850, thetensioning instrument 800 has a release shaft 900 with a button end 902connected to the button 840 and a plunger end 904 configured to abut areceiving surface 906 of the drive socket 874, as shown in FIGS. 41 and42. The release shaft 900 is slidably received with a throughbore 908 ofthe drive shaft 850 and is biased in direction 909 by a spring 980, asshown in FIG. 50. Pressing the button 840 in direction 910 shifts therelease shaft 900, tension drive 872, and the tension ring 932 indirection 910, as shown in FIG. 51. The plunger end 904 has a circular,flat pusher surface 911 with a diameter thereacross that is less than awidth 913 of the drive socket 874 between sidewalls 876, 878 but largerthan an opening 915 in the receiving surface 906, as shown in FIGS. 41and 42. The clearance between the plunger end 904 and the socketsidewalls 876, 878, 879, 881 and the sliding contact between the pushersurface 911 and the receiving surface 906 allows the tension drive 872,and the tension ring 932 carried thereon, to rotate about the plungerend 904 once the release shaft 900 has shifted the tension drive 872 outof engagement with the drive shaft 850, as shown in FIG. 51. The tensiondrive 872 and the tension ring 932 may then be rotated by the tension inthe surgical cable 805 as the tension is released after disengagement ofthe drive shaft 850 and the tension drive 872.

The tensioning instrument 800 includes a cable gripping mechanism 930that locks onto the surgical cable 805 with rotation of the handle 820,as shown in FIGS. 41, 46, and 47. In one form, the cable grippingmechanism 930 includes the tension drive 872 and the tension ring 932disposed coaxially thereon. When the tension drive 872 is rotated byturning the handle 820, the tension drive 872 shifts rotationally withina central opening 940 of the tension ring 932 and causes a circularouter surface 942 of the tension drive 872 to slide along an annularinner surface 944 of the tension ring 932, as shown in FIGS. 42, 44, 46,and 47. Shifting the tension ring 932 about the tension drive 872 causesthe tension drive 872 and the tension ring 932 to fix the tension drive872 and the tension ring 932 to the surgical cable 805, as discussed ingreater detail below. With the tension drive 872 and the tension ring932 fixed to the surgical cable 805, continued turning of the handle 820continues to turn the tension drive 872 and the tension ring 932,further winds the surgical cable 805 onto the tension ring 932, andfurther tensions the surgical cable 805.

The cable gripping mechanism 930 also includes the bias assembly 946configured to limit relative rotation between the tension drive 872 andthe tension ring 932 and return the tension ring 932 to the pass throughorientation about the tension drive 872. The bias assembly 946 has atension pin 948 sized to fit within a pin aperture 950 of the tensionring 932 and a base 954 secured to the tension ring 932 to fix thetension pin 948 to the tension ring 932, as shown in FIGS. 41, 44, and46. The base 954 is preferably welded or otherwise secured to thetension ring 932 after the tension drive 872 has been positioned withinthe central opening 940 of the tension ring 932. Further, the tensionpin 948 may extend radially inward from the tension ring 932 with atension ring tooth 952 disposed within a pin slot 960 in an outer wall962 of the tension drive 872 (see FIGS. 42, 43, and 46). The engagementbetween the tension pin 948 and the pin slot 960 captures the tensiondrive 872 within the central opening 940 of the tension ring 932 whilepermitting a predetermined amount of relative rotary motiontherebetween.

With reference to FIGS. 43 and 46, the bias assembly 946 furtherincludes a spring 964 having an end 966 for engaging a spring seat 968of the tension drive 872 and an opposite end 969 abutting the tooth 952of the tension pin 948. The pin slot 960 extends along a circumferenceof the outer wall 962 a distance that is longer than a diameter of thetension pin 948 to permit the tension pin 948 to slide within the slot960 as the tension drive 872 moves rotationally relative to the tensionring 932. More specifically, movement of the tension drive 872 indirection 970 brings spring seat 968 toward the tooth 952 of the tensionpin 948 and compresses the spring 964, as shown in FIG. 47. Thecompressed spring 964 provides a restoring force that tends to shift thetension ring 932 in direction 970 and re-align apertures 1014, 1016 ofthe tension ring 932 with the through opening 1018 of the tension drive872 once tension has been released from the surgical cable 805, such asafter a locking device 809 has been crimped to secure the surgical cable805 around bones and the drive shaft 850 has been disengaged from thetension drive 872. In this manner, the cable gripping mechanism 930 mayautomatically release the surgical cable 805 and permit the surgicalcable 805 to be withdrawn from the tensioning instrument 800 aftertension has been released in the surgical cable 805.

The release mechanism 842 includes the spring 980 having one end 982abutting a cap 984 welded to the body 808 at points 986, as shown inFIG. 48, and an opposite end 988 abutting a washer 981 for biasing thetension drive 872 in direction 982, as shown in FIG. 49. The spring 980biases the washer 981 against the tension drive 872 and maintains thetension drive socket 874 firmly engaged with the drive shaft key 870. Toovercome the bias force of the spring 980 and disengage the tensiondrive socket 874 from the drive shaft key 870, the release button 840 ispressed to shift the release shaft 900 in direction 910 which moves thetension drive 872 in direction 910, as discussed in greater detail aboveand shown in FIGS. 50 and 51.

The operation of the tensioning instrument 800 is substantiallyidentical to the operation of the tensioning instrument 122 such thatthe following description of the operation of the tensioning instrument800 will begin at the point where the surgical cable 805 has beenadvanced through the distal end 802 of the tensioning instrument 800,out from the proximal end 812, and pulled tightly to remove slack fromthe surgical cable, as shown in FIG. 46. More specifically, with thehandle 820 in the vertical orientation and the tension drive 872 and thetension ring 932 in the pass through configuration shown in FIG. 46, thesurgical cable 805 may be readily advanced through the opening 807 ofthe rotary tensioning device 824 and out the outlet opening 810. Thesurgical cable 805 extends through a guide tube 1009 of the distal end802, upward beyond an aperture 1010 in the body 808, through the opening807 of the rotary tensioning device 824, and outward through the outletopening 810, as shown in FIG. 46. The aperture 1010 allows a surgeon toview the surgical cable 805 within the body 808 which may be useful whenadvancing the surgical cable 805 into the through opening 807 of therotary tensioning device 824.

The handle 820 is then turned in the wind up direction 970 tosubstantially simultaneously fix the cable gripping mechanism 930 to thesurgical cable 805 at two positions along the surgical cable 805 as wellas tension the surgical cable 805 by winding the surgical cable 805 ontothe rotary tensioning device 824. The handle 820 is shown in FIG. 47 ashaving been rotated a quarter turn in the wind up direction 970 toillustrate the operation of the internal components of the tensioninginstrument 800. It will be appreciated that the handle 820 may be turnedfarther to continue to take up the surgical cable 805 onto the tensionring 932. Further, the cavity 886 of the body 808 includes gaps 1013,1015 disposed radially between the tension ring 932 and the body 808that are sized to provide clearance between coils of the surgical cable805 and the body 808 as the surgical cable 805 is drawn onto the tensionring 932, as shown in FIG. 49. These gaps 1013, 1015 permit relativelylong sections of the surgical cable 805 to be wound around the tensionring 932 with continued turning of the handle 824.

Turning the handle 820 in the wind up direction 970 rotates the tensiondrive 872 in direction 970 and causes a surgical cable distal section1030 to be drawn onto a lower portion 1032 of the tension ring 932 and asurgical cable proximal section 1034 to be drawn onto an upper portion1036 of the tension ring 932. Drawing the surgical cable distal section1030 onto the tension ring 932 tensions the surgical cable 28 betweenthe tension ring 932 and the distal end 802 of the tensioning tool 800which is positioned against the locking device 809. The tension in thesurgical cable 805 shifts the tension ring 932 in direction 971 relativeto the tension drive 872 and causes the tension ring 932 to pinch thesurgical cable 805 at intersections 1042, 1044 between the apertures1014, 1016 of the tension ring 932 and the central through opening 1018of the tension drive 872, as shown in FIG. 47. Further, shifting of thetension ring 932 about the tension drive 872 moves the spring seat 968toward the tension pin 952 and compresses the spring 964.

Once a desired amount of tension has been applied to the surgical cable805, and the pawl 884 resisting turning of the drive shaft 850 in thepay out direction 971, the surgical cable 805 is secured in positionsuch as by crimping the locking device 809. Next, the release button 840is pressed in direction 910 to shift the release shaft 900 in direction910, as shown in FIGS. 50 and 51. The plunger end 940 presses againstthe receiving surface 906 (see FIG. 42) of the drive socket 874, shiftsthe tension drive 872 and the tension ring 932 in direction 910, andshifts the tension drive socket 874 out of engagement with the driveshaft key 870. In this position, the tension drive 872 and the tensionring 932 may rotate in the pay out direction 971 relative to the driveshaft 850 so that any tension previously applied to the surgical cable805 by turning of the handle 820 is released from the surgical cable805. Further, with the release button 840 depressed, the surgical cable805 can be withdrawn in direction 1060 from the distal end 802 of thetensioning instrument 800, as shown in FIG. 51. Because the tensiondrive 872 and tension ring 932 are disconnected from the drive shaft key870, pulling the surgical cable 805 in direction 1060 off of the tensionring 932 causes the tension drive 872 and the tension ring 932 to rotateabout the plunger end 940 in pay out direction 971 and permits thesurgical cable 805 to be paid out from the tension ring 932. Once thesurgical cable 805 has been withdrawn from the tensioning instrument800, the tensioning instrument 800 can be removed from the surgical siteand the surgical cable 805 cut to length as desired.

With reference to FIGS. 53-65, a cable tensioning instrument 1500 isshown that permits rapid and easy-to-use tensioning of surgical cable24. The tensioning instrument 1500 has a body 1502 with a scallopedprofile 1504 and a rotary tensioning device 1510 with a tension drive1572 that is partially visible from outside of the body 1502, as shownin FIG. 53. The instrument 1500 has a drive 1512 including a handle 1513coupled to the rotary tensioning device 1510 so that turning of thehandle 1513 produces associated turning of the rotary tension device1510 (and tension drive 1572 with etch mark 1573 thereon). Withreference to FIGS. 53 and 63, the body 1502 has a distal end 1520 withan inlet opening 1522, a proximal outlet opening 1524, a passage 1823(see FIG. 63) extending therebetween, and a through opening 1811 of therotary tensioning device 1510. In a manner similar to the use of thetensioning instrument 122 discussed above with reference to FIGS. 10-13,the leading end portion 28 of the cable 24 is inserted into the inletopening 1522, along the passage 1823 and through the opening 1811, andoutward from the body outlet opening 1522 in order to initially connectthe tensioning instrument 1500 to the cable 24.

With the cable 24 extending through the tensioning instrument 1500, asurgeon may move the tensioning instrument 1500 along the surgical cable24 toward the bone plate 20 with one hand and pull any slack out of thesurgical cable 24 with the other hand, as discussed above with respectto tensioning instruments 122 and 800. Next, the handle 1513 is turnedto turn the rotary tensioning device 1510 and wrap cable 24 onto therotary tensioning device 1510. Turning the rotary tensioning device 1510within the body 1502 reconfigures the grip device 1514 from apass-through configuration where the cable 24 may be advanced throughthe rotary tensioning device opening 1811 between the tension drive 1572and the clamp body 1800 (see FIGS. 63 and 64), to a grippingconfiguration where the tension drive 1572 and clamp body 1800 areshifted together and clamp the cable 24 (see FIG. 65). Continued turningof the handle 1513 continues to wrap cable onto the rotary tensioningdevice 1510 while the tension drive 1572 and clamp body 1800 fix thecable 24 to the rotary tensioning device 1510. This turning of therotary tensioning device 1510 while maintaining the 1572 and clamp body1800 fixed on the cable 24 applies tension to the cable 24.

It will be appreciated that the tensioning instrument 1500 is similar inmany respects to the structure and operation of the tensioninginstruments 122, 800 discussed above such that the following discussionwill highlight differences between the instrument 1500 and theinstruments 122, 800. For example, the rotary tensioning device 1510 hasa grip device 1514 (see FIG. 54) that clamps the cable 24 between faces1820 (see FIG. 58), 1870 (see FIG. 60) of the tension drive 1572 and aclamp body 1800 rather than clamping a cable between the portions oftension ring 932 and tension drive 872 as in the instrument 800 (seeFIGS. 46 and 47).

With reference to FIG. 54, the tensioning instrument 1500 includes aratchet assembly 1530 configured to selectively permit turning of therotary tensioning device 1510. The ratchet assembly 1530 includes a pawlassembly 1532 having a pawl 1534 with a split tooth 1536, the pawl 1534being slidably received within a pawl sleeve 1540. The pawl 1534 islongitudinally movable within the pawl sleeve 1540 and is biased by aspring 1542 into engagement with a drive shaft 1550 (which is secured atits other end to the handle 1513). The pawl tooth 1536 engages teeth1664 on a ratchet portion 1560 of the drive shaft 1550, as shown in FIG.54. As will be discussed in greater detail below, the ratchet assembly1530 has a different configuration than the ratchet assembly 826 inorder to provide different assembly and disassembly of the instrument1500.

The tensioning instrument 1500 also has a different connection betweenthe drive shaft 1550 and the rotary tension device 1510 than thecomponents of the tensioning instrument 800. In particular, the driveshaft 1550 has a drive portion 1570 that is selectively engaged via ballbearings 1586 with the tension drive 1572 of the rotary tension device1510. With reference to FIGS. 54 and 56, the drive shaft 1550 has aninner throughbore 1580 with a release shaft 1582 slidably disposedtherein. The drive shaft drive portion 1570 includes radially outwardlyextending openings 1584 (see FIG. 56) that receive the ball bearings1586 and are sized to permit the ball bearings 1586 to shift inwardlyand outwardly within the openings 1584 based upon the position of therelease shaft 1582. As shown in FIG. 56, the release shaft 1582 has anenlarged collar 1590, a neck 1592, and an enlarged head 1594 at a distalend thereof. The head portion 1594 has an outer diameter sized to fillsubstantially the entire throughbore 1580 and shift a portion of each ofthe ball bearings 1586 outwardly into pockets 1600 (see FIG. 57 and FIG.61).

With the drive shaft drive portion 1570 engaged in the socket 1576 andthe ball bearings 1586 shifted outward by the release shaft head 1590into engagement with the pockets 1600, turning of the drive shaft 1550produces turning of the tension drive 1572, as shown in FIG. 61. Forexample, if the handle 1513 is turned in a wind up direction 1650 toapply tension to the cable 24 once the cable 24 has been advancedthrough the instrument 1500 (see FIG. 53), the drive shaft 1550 willturn in the wind up direction 1650 while the cable 24 will resist thetensioning and tend to turn the tension drive 1572 in a pay outdirection 1652. However, a section of each ball bearing 1586 is disposedin the drive shaft openings 1584 while the remaining section extendsoutward into the tension drive pockets 1600. The ball bearings 1586 arethereby engaged with both the drive shaft drive portion 1570 and thetension drive socket 1576 and inhibit relative movement between thedrive shaft 1550 and the tension drive 1572. Thus, turning the handle1512 and drive shaft 1550 in the wind up direction 1650 with sufficienttorque produces turning of the tension drive 1572 (and clamp body 1800connected thereto) and applies tension to the cable 24. It will beappreciated that the ball bearings 1586 are preferably made of asufficiently hard material to resist the shearing loads applied to theball bearings 1586 by the tension drive 1572 and the drive shaft 1550.

To disengage the drive shaft 1550 from the tension drive 1572, a button1610 connected to the release shaft 1582 is pressed to shift the releaseshaft 1582 in direction 1612 toward a release position, as shown in FIG.61. This aligns the neck 1592 of the release shaft 1582 with theradially extending openings 1584 of the drive shaft drive portion 1570,as shown in FIG. 62. Moving the neck 1592 into alignment with theopenings 1584 moves a gap 1612 between the drive shaft 1550 and therelease shaft 1582 into communication with the openings 1584 whichpermits the ball bearings 1586 to shift inwardly. To aid the ballbearings 1586 in shifting inwardly, the pockets 1600 of the tensiondrive 1572 have curved inner surfaces 1620 (see FIG. 57) that engageouter surfaces 1622 (see FIG. 55) of the ball bearings 1586 and cam theball bearings 1586 radially inward upon turning of the now-disengagedtension drive 1572 about the drive shaft drive portion 1570. Forexample, once the button 1610 has been pressed in direction 1612 and theshaft 1582 shifted to its release position, tension in the cable 24 mayturn the tension drive 1572 in the payout direction 1652 because theball bearings 1586 are no longer held in the outwardly biased positionby the release shaft 1582. The resulting turning of the now-disengagedtension drive 1572 about the drive shaft drive portion 1570 causes thepocket surfaces 1620 to cam the bearings 1586 radially inward into thegap 1612 to provide clearance for the tension drive 1572 about the driveshaft drive end 1570.

The ratchet assembly 1530 includes a spring 1630 that biases against thebutton 1610 and shifts the release shaft 1582 backward in direction1632, as shown in FIG. 62. Shifting the release shaft 1582 backwardreturns the release shaft 1582 to its engaging position and re-alignsthe release shaft head 1594 with the ball bearings 1586 to shift theball bearings 1586 back into engagement with the tension drive socketpockets 1600. With reference to FIG. 56, the release shaft 1582 has atapered cam surface 1634 extending outwardly from the neck 1592 towardthe enlarged head 1594. The cam surface 1634 is configured to engage theball bearings 1586 and cam the ball bearings 1586 radially outwardwithin the openings 1584 upon return of the release shaft 1582 indirection 1632. This aids in returning the ball bearings 1586 to theirengaged position within the drive shaft socket pockets 1600. With therelease shaft 1582 returned to its engaged position, as shown in FIG.61, turning of the handle 1513 in the wind up direction 1650 will againproduce corresponding turning of the tension drive 1572 and the clampbody 1800 in the wind up direction 1650 and apply tension to the cable24 if the cable 24 is present in the instrument 1500.

The pawl 1534 of the tensioning instrument 1500 is different than thepawl 884 discussed above because the pawl 1534 is slidably mountedwithin the pawl sleeve 1540, as shown in FIGS. 54 and 55. Further, thepawl 1534 has a split tooth 1536 with portions disposed on oppositesides of a central fin 1660 of the pawl sleeve 1540 once the pawl 1534has been positioned within the pawl sleeve 1540, as shown in FIGS. 55and 61. The fin 1660 fits into a channel 1662 disposed between sets ofthe teeth 1664 of the drive shaft ratchet portion 1560, as shown in FIG.55. The engagement of the fin 1660 in the channel 1662 restricts axialmovement of the drive shaft 1550 in direction 1612 and maintains thedrive shaft 1550 mounted in the body 1502 against a bearing 1663, asshown in FIG. 54. On the other side of the body 1502 from the bearing1663, the instrument has a nut 1677 that threadingly engages the driveshaft 1550 and further secures the drive shaft 1550 in position on thebody 1502.

With reference to FIGS. 55 and 61, the pawl assembly 1532 includes adisassembly button 1666 and a pin 1668 that connects the disassemblybutton 1666 to the pawl 1534. The pin 1668 extends through a slot 1672in the body 1502 and through a slot 1670 in the pawl sleeve 1540, asshown in FIG. 61. The body slot 1672 restricts the pin 1668 and pawl1534 to axial movement up and down within a cavity 1669 of the body 1502and the engagement of the pin 1668 within the pawl sleeve slot 1670restricts turning of the sleeve 1540 about the pawl 1534. Thus, both thepawl 1534 and pawl sleeve 1540 are generally restricted to axial,up-and-down movement within the body cavity 1669.

To disassemble the instrument 1500, a user presses the button 1666 indirection 1673 to shift the pin 1668 and pawl 1534 connected thereto indirection 1673 and disengage the pawl tooth 1536 from the drive shaftratchet teeth 1664. Continued movement of the button 1666 in direction1673 contacts the pin 1668 against a lower end of the slot 1670 of thepawl sleeve 1540 and shifts the pawl sleeve 1540 in direction 1673 aswell. Movement of the pawl sleeve 1540 disengages the fin 1660 from thedrive shaft channel 1662 such that both the pawl 1534 and the pawlsleeve 1540 are disengaged from the drive shaft 1550. The handle 1513can then be moved in direction 1612 (see FIG. 61) to shift the tensiondrive 1572, clamp body 1800, and drive shaft drive portion 1580 outwardfrom a cavity 1675 of the body 1502, as shown in FIG. 54. In one form,the button 1610 is laser welded to the release shaft 1582 such that thedrive shaft 1550 is restricted from being completely removed from thebody 1502. In another form, the button 1610 is connected with threads tothe release shaft 1582, such that the button 1610 and the nut 1677 canbe unthreaded from the release shaft 1610 and the drive shaft 1550,respectively, to permit the drive shaft 1550 and release shaft 1610 tobe fully removed from the body 1502, as shown in FIG. 54.

Another advantage of the pawl assembly 1532 is that the pawl 1534 andpawl sleeve 1540 are separate components that independently performdifferent functions. More specifically, the pawl sleeve 1540 and fin1660 thereof engage the drive shaft 1550 to restrict axial movement ofthe drive shaft 1550. The pawl 1534 operates in an orthogonal directionwith the pawl tooth 1536 moving up and down as the pawl tooth 1536travels up and down along the drive shaft ratchet teeth 1664. Thus, thepawl assembly 1532 uses the pawl 1534 and the pawl sleeve 1534 toprovide two different functions in a compact package within theinstrument 1500.

More specifically, frictional engagement between the pawl sleeve fin1660 and sidewalls 1676 of the ratchet teeth 1664 (see FIG. 55) maycause the pawl sleeve 1540 to travel axially downward within the cavity1669 (see FIG. 61) with turning of the drive shaft 1550 in the wind updirection 1650. However, this axial movement of the pawl sleeve 1540generally does not produce axial movement of the pawl 1534 anddisengagement of the pawl tooth 1536 from the drive shaft ratchet teeth1664. Instead, the pawl sleeve 1540 shifts downwardly along the outersurface of the pawl tooth 1536 toward the distal end 1520 of theinstrument 1500. The spring 1542, however, continues to bias the pawl1534 and tooth 1536 in an opposite direction toward the drive shaft 1550and into engagement with the drive shaft ratchet teeth 1664 thereofdespite any slight axial movements of the pawl sleeve 1540. Thus, thepawl assembly 1532 reduces the likelihood of unintentional disengagementof the pawl 1534 from the drive shaft drive portion 1570.

With reference to FIGS. 57-59, the tension drive 1572 has structuresthat guide and engage the clamp body 1800 during turning of the rotarytensioning device 1510 and reconfiguring of the grip device 1514 fromthe pass-through configuration to the gripped configuration. Inparticular, the tension drive 1572 has a drive plate 1810 and anexterior plate 1812 that define a recess 1814 therebetween sized toreceive the clamp body 1800 therein, as shown in FIG. 57. The driveplate 1810 has the drive socket 1576 formed therein and the externalplate 1812 forms an outer wall of the tensioning instrument 1500 that isvisible from the exterior of the tensioning instrument 1500, as shown inFIG. 53. The etch mark 1573 is generally parallel to a groove 1822 ofthe tension drive 1572 such that the etch mark 1573 is aligned with athrough opening 1811 of the grip device 1514 formed by the groove 1822of the tension drive 1572 and a groove 1824 of the clamp body 1800, asshown in FIGS. 57, 60, and 63. By turning the handle 1513 to align theetch mark 1573 with an etch mark 1813 (see FIG. 53) on the body 1502,the surgeon can visually confirm that the opening 1811 is aligned with athrough passage 1823 of the body 1502, as shown in FIG. 63. The cable 24can then easily be passed into the inlet opening 1522, through the bodypassage 1823, through the rotary tensioning instrument opening 1811, andoutward from the outlet opening 1524.

With reference to FIG. 59, the plates 1810, 1812 may extend from a face1820 of the tension drive 1572 on opposite sides of the recess 1814. Theface 1820 has the cable-receiving groove 1822 formed therein thatcooperates with the groove 1824 (see FIG. 60) of the clamp member 1800to define the through opening 1811 of the grip device 1514, as will bediscussed in greater detail below. With reference to FIGS. 54 and 58,the tension drive face 1820 has a pair of blind bores 1830 that receivesliding pins 1832. The pins 1832 have support ends 1834 (see FIG. 54)that are fixed within the blind bores 1830 and free ends 1836 (see FIG.55) extending outward from the tension drive face 1820 into slidingengagement with a circumferential retention groove 1840 of the driveshaft drive portion 1570, as shown in FIG. 55. The sliding pin free ends1836 extend generally perpendicular to the length of the drive shaft1550 and are oriented to fit into the groove 1840 on opposite sides ofthe drive shaft 1550. With reference to FIG. 60, the clamp member has arecess 1850 that provides clearance for the sliding pin free ends 1836.This clearance permits the clamp member 1800 to move relative to thetension drive 1572 without contacting or interfering with the engagementof the sliding pin 1832 with the drive shaft retention groove 1840.Similarly, the tension drive 1572 has a relatively large opening 1835that receives a portion of a pin 1837 which extends outward from theclamp body 800. Because the opening 1835 is larger than the pin 1837,the opening 1835 retains the pin 1837 therein while permits the clampbody 1800 to move relative to the tension drive 1572 between the passthrough and gripped configurations.

With reference to FIGS. 55 and 58, the tension drive face 1820 alsoincludes blind bores 1860 that receive springs 1862 and clamp plungers1864 therein. The clamp plungers 1864 can slide in a piston-like mannerwithin the blind bores 1860 with distal ends 1866 of the clamp plungers1864 biased by the springs 1862 into engagement with a face 1870 of theclamp body 1800, as shown in FIG. 55. Clamp plungers 1864 operate toseparate the clamp body 1800 from the tension drive 1572 once thetension drive 1572 and clamp body 1800 have been turned to a passthrough configuration where the tension drive 1572 and clamp body 1800can move apart, as shown in FIG. 64. During assembly, the clamp plungers1864 are inserted into the bores 1860 after the springs 1862 and aportion of the tension drive 1572 surrounding the opening of the bores1860 can be deformed to capture the plungers 1864 and springs 1862 inthe bores 1860.

With reference to FIG. 60, the clamp body 1800 has a pair of end walls1872, 1874 on opposite sides of a curved winding portion 1876. Thewinding portion 1876 forms a partially discontinuous spool incombination with a winding portion 1880 of the tension drive 1572 (seeFIG. 59). The end walls 1872, 1874 of the clamp body 1800 each include aprotrusion 1890 having an engagement surface, such as outer curvedsurface 1892, which is configured to engage a locking surface of thebody 1502, such as curved inner surface 1900 of the cavity 1675, asshown in FIG. 63. With the tension drive 1572 and the clamp body 1800 inthe pass-through configuration (see FIG. 63), the clamp end wallprotrusions 1890 are positioned within a complementary recess 1904 ofthe body cavity 1902, as shown in FIG. 64. In this orientation, theclamp plungers 1864 can press against the clamp body 1800 and separatethe clamp body 1800 from the tension drive 1572 as discussed above. Thebiasing force of the plungers 1864 against the clamp body 1800 positionsthe tension drive 1572 and clamp body 1800 so that the rotary tensioningdevice through opening 1811 has a release or pass-through diameter 1910.As shown in FIG. 64, there is a gap 1912 between the faces 1820, 1870 ofthe tension drive 1572 and the clamp member 1800 when the tension drive1572 and the clamp body 1800 are in the pass-through configuration.

Turning the handle 1513 in the wind up direction 1650 brings theprotrusion outer surface 1892 into camming engagement with the bodyinner surface 1900 which shifts the clamp member 1800 toward the face1820 of the tension drive 1572, as shown in FIG. 65. Thus, turning thehandle 1513 in the wind up direction 1650 reconfigures the tension drive1572 and the clamp body 1800 from the pass-through configuration to thegripped configuration. With reference to FIG. 65, the rotary tensioningdevice through opening 1811 has an engagement diameter 1920 that issmaller than the pass-through diameter 1910 once the tension drive 1572and clamp body 1800 have been shifted to the gripped configuration. Inparticular, the faces 1820, 1870 are brought into engagement with oneanother and the grooves 1822, 1824 compress the cable 24 therebetween.This fixes the locking clamp member 1800 and tension drive 1572 onto thecable 24. It will be appreciated that the grooves 1822, 1824 may havesurface treatments or structures that increase the frictional engagementof the tension drive 1572 and clamp body 1800 with the cable 24.

To release the grip device 1514 from the cable 24, the button 1610 ispressed to shift the release shaft 1582 in direction 1612 (see FIG. 61)and disengage the tension drive 1572 from the drive shaft 1550, asdiscussed above. The tension in the cable 24 will then turn the tensiondrive 1572 and the clamp member 1800 back in the pay out direction 1652which pays out the cable 24 from the winding portions 1876, 1880 of thetension drive 1572 and the clamp member 1800.

With reference to FIGS. 66-69, a bone anchor 2000 and a driver tooldistal end 2002 are shown. The bone anchor 2000 and driver tool distalend 2002 are substantially similar to the bone screw 46 and driver 180discussed above such that the differences from the bone screw 46 anddriver 180 will be highlighted. The bone anchor 2000 has a head portion2004 with a substantially cross-shaped drive recess 2006 with axiallyextending walls 2008 that extend to a floor 2010 of the recess 2006. Thefloor 2010 has a blind bore 2012 formed therein. The anchor 2000 has ashank 2005 depending from the head portion 2004. The shank 2005 may bethreaded in a complimentary manner to threads 2007 on the head portion2004.

With reference to FIG. 68, the driver distal end 2002 has cross-shapeddrives 2020 configured to engage the walls of the drive recess 2006. Thedistal end 2002 also has a retention device 2022 including a taperedpost 2024 which forms a press fit engagement with the blind bore 2012 ofthe bone anchor 2000.

Those skilled in the art will recognize that a wide variety ofmodifications, alterations, and combinations can be made with respect tothe above described embodiments without departing from the spirit andscope of the invention, and that such modifications, alterations, andcombinations, are to be viewed as being within the scope of theinvention.

What is claimed is:
 1. An instrument for tensioning a cable, theinstrument comprising: a body having a locking surface; a rotarytensioner rotatably mounted to the body and configured to have a cablewound thereabout; a ratchet assembly that permits turning of the rotarytensioner in a wind up direction and resists turning of the rotarytensioner in a pay out direction; a pair of gripping portions of therotary tensioner that are rotatable relative to the body andreconfigurable with respect to one another with turning of the rotarytensioner in the wind up direction from a pass-through configurationthat permits the cable to be drawn through the gripping portions to agripping configuration that fixes the cable relative to the grippingportions for generating tension in the fixed cable; and a cam surface ofthe rotary tensioner configured to cammingly engage the body lockingsurface with turning of the rotary tensioner in the wind up direction tocause the pair of gripping portions to be reconfigured from thepass-through configuration to the gripping configuration.
 2. Theinstrument of claim 1 wherein the gripping portions of the rotarytensioner are spaced apart with the gripping portions in thepass-through configuration and the gripping portions are closer togetherin the gripping configuration to fix the cable to the gripping portions.3. The instrument of claim 1 further comprising a drive operablyconnected to the rotary tensioner for turning the rotary tensioner; andthe ratchet assembly engages the drive to resist turning of the driveand the rotary tensioner in the pay out direction.
 4. The instrument ofclaim 1 further comprising a drive for turning the rotary tensioner; andthe ratchet assembly includes an actuator having a release position thatdisengages the drive from the rotary tensioner so that the ratchetassembly permits turning of the rotary tensioner in the pay outdirection and a tensioning position that engages the drive to the rotarytensioner so that the ratchet assembly resists turning of the rotarytensioner in the pay out direction.
 5. The instrument of claim 1 whereinthe body has a passage sized to receive the cable and the rotarytensioner has a through opening alignable with the body passage.
 6. Theinstrument of claim 1 wherein the gripping portions include a pivotconnection therebetween and the camming engagement of the rotarytensioner cam surface and the body locking surface pivots at least oneof the gripping portions relative to the other with turning of therotary tensioner in the wind up direction and reconfigures the grippingportions from the pass-through configuration to the grippingconfiguration.
 7. The instrument of claim 1 wherein the rotary tensionerincludes a spring that biases the gripping portions apart to urge thegripping portions to the pass-through configuration thereof.
 8. Theinstrument of claim 1 wherein the rotary tensioner include a protrusionwith the cam surface and the body includes a recess sized to receive theprotrusion.
 9. The instrument of claim 1 wherein one of the grippingportions includes a pair of spaced plate portions and the other grippingportion is received between the plate portions.
 10. The instrument ofclaim 1 wherein the body includes a tubular portion extending away fromthe rotary tensioner, the tubular portion having a passage sized toreceive a cable, and the rotary tensioner has a through openingextending between the gripping portions that is alignable with thepassage of the body tubular passage.
 11. The instrument of claim 1wherein the gripping portions include outer arcuate surfaces alignedwith one another to form a spool surface around which the cable iswound.
 12. An instrument for tensioning a cable, the instrumentcomprising: a body having a locking surface; a rotary tensionerrotatably mounted to the body and configured to have a cable woundthereabout; a ratchet assembly that permits turning of the rotarytensioner in a wind up direction and resists turning of the rotarytensioner in a pay out direction; a pair of gripping portions of therotary tensioner rotatable relative to the body, the gripping portionsconfigured to permit the cable to be advanced therebetween; and a camsurface of one of the gripping portions configured to cammingly engagethe body locking surface with turning of the rotary tensioner in thewind up direction and shift the one gripping portion toward the othergripping portion and fix the gripping portions to the cable.
 13. Theinstrument of claim 12 further comprising a drive operably connected tothe rotary tensioner for turning the rotary tensioner; and the ratchetassembly engages the drive to resist turning of the drive and the rotarytensioner in the pay out direction.
 14. The instrument of claim 12wherein the body includes a cavity and the rotary tensioner is rotatablymounted to the body in the cavity.
 15. The instrument of claim 12wherein the body has a passage sized to receive the cable and the rotarytensioner has a through opening alignable with the body passage.
 16. Theinstrument of claim 12 wherein the gripping portions include a pivotconnection therebetween and the cam surface of the one gripping portionis configured to cause the one gripping portion to pivot toward theother gripping portion with turning of the rotary tensioner in the windup direction.
 17. The instrument of claim 12 wherein the rotarytensioner include a spring that biases the gripping portions apart. 18.The instrument of claim 12 wherein the one gripping portion includes aprotrusion having the cam surface thereon and the body includes a recesssized to receive the protrusion.
 19. The instrument of claim 12 whereinthe other gripping portion includes a pair of spaced plate portions andthe one gripping portion is received between the plate portions.
 20. Theinstrument of claim 12 wherein the body includes a tubular portionextending away from the rotary tensioner, the tubular portion having apassage sized to receive a cable, and the rotary tensioner has a throughopening extending between the gripping portions that is alignable withthe passage of the body tubular passage.